Exterior building material having a hollow thin wall profile and an embossed low gloss surface

ABSTRACT

A building product which includes a hollow extrudate, unitary reinforcing ribs resisting collapse of the hollow extrudate and, in an embodiment, an exterior surface comprises a low gloss, textured pattern having a gloss level of less than about 50 on a 60° glossmeter, in which the textured pattern extends for about 2-20 feet. Methods and an apparatus for manufacturing such products are also provided by this invention.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of both U.S. Provisional ApplicationNo. 60/807,081, filed Jul. 12, 2006 and U.S. Provisional Application No.60/807,082, filed Jul. 12, 2006.

This application is related to U.S. application Ser. No. 10/281,795,filed Oct. 28, 2002, of Byeong Jo and John Peavey, entitled “PlasticDecking System Reinforced with Fiberglass Reinforced ThermoplasticComposites” (D0932-00200); U.S. application Ser. No. 09/190,038, filedNov. 12, 1998, of Thomas Gilbert, David Jacobson, and Rick Lappin,entitled “Shaped Polymeric Articles” (D0932-00088); U.S. applicationSer. No. 09/735,681, filed Dec. 13, 2000, of Thomas Gilbert, KennethBosler and Steven Booz, entitled “Staggered Look Shake Siding”, now U.S.Pat. No. 6,737,008, issued May 18, 2004 (D0932-00230); and U.S.application Ser. No. 11/247,620, filed Oct. 11, 2005, of Jong P. Jeng,entitled “Building Material Having a Fluorocarbon Based Capstock layerand Process of Manufacturing Same with Less Dimensional Distortion”(D0932-00593); the entirety of which are incorporated herein byreference. The Examiner's attention is drawn to the prior art cited, orotherwise of record, in these related applications.

FIELD OF THE INVENTION

This invention relates to substantially hollow, closed, thin wallprofile building materials having a low gloss textured pattern disposedcontinuously along one or more surfaces thereof.

BACKGROUND OF THE INVENTION

There have been a number of polymeric products made to look like naturalwood for decking and siding applications. Such products are formed byextrusion and embossing processes, or by injection molding in a patternmold to simulate a wood grain or pattern. Such products comprise apainted or otherwise “decorated” or printed pattern to simulate wood orother materials, such as marble or natural stone, for example. Suchteachings are provided in Franco et al., US2005/0053767; Giacchino, US2005/0127345; Barre et al., U.S. Pat. No. 5,331,602; Anstadt et al.,U.S. Pat. No. 4,141,944; Bosler, U.S. Pat. Nos. 5,906,840; 5,314,325,6,823,794 and 6,641,384; Cameron et al., U.S. Pat. No. 5,053,176;Dorchester et al., U.S. Pat. Nos. 5,866,054 and 5,869,176; Saloom, U.S.Pat. No. 5,387,381; and Soda et al., U.S. Pat. No. 3,936,518, which arehereby incorporated by reference. Most of these disclosures, other thanthe Bosler patents, relate to the use of embossing rolls locatedimmediately downstream of the extrusion die. The embossing operation isdesigned to emboss the surface configuration, or provide ornamentationonto the capstock layer side of a plastic sheet. The embossing rollsapply tension to the sheet of plastic to draw the sheet of plastic downto a particular dimension. Following embossing, the embossed sheet istypically preformed in a die into a rough version of a siding profile.See, for example, Dorchester et al. U.S. Pat. No. 5,869,176, at col. 6,lines 11-26. While siding can be embossed readily with good effect, thehigh pressure of embossing rolls is ill suited for hollow profiles, suchas fence boards and hollow decking planks, which would likely collapseunder such pressure.

Multiple hollow fence board products made of thermoplastic materials areavailable in the market. Present hollow, semi-hollow, thin walled fenceboards made of polymer based materials (neat, composite, or withfillers) made in extrusion processes have a surface which is smooth orenhanced by longitudinal, machine- or extrusion-direction texture,lines, ribs, or depressions. Such products do not have the look ofnatural wood, such as softer areas indicative of environmental wear, orharder areas which are generally more resistant to environmental wear.These hard and soft areas form peaks and valleys on the natural woodboard surface following natural wood patterns which do not always lineup with the machine- or extrusion-direction of synthetically madematerials. Furthermore, hollow, thin wall fence board products currentlyavailable in the market exhibit a high surface gloss which reveals thetrue character of this material, and often make them undesirable onaesthetic grounds.

Continuous and semi-continuous processes for creating patterns onextruded plastic sheets have been used in the building componentsindustry for a number of years. Some prior systems have disclosed rigidlinked patterns for forming shaped impressions in an extruded sheetmaterial. Unfortunately, such rigid shaped patterns tend to formunsightly horizontal seams in the material. Other systems have usedpattern forms on rotating cylindrical drums. Although these processesare continuous, and do not produce horizontal seams, they often requireexpensive additional equipment and instrumentation to align the arcuatesurface of the pattern with the relatively flat surface of the product,and to avoid, or correct, unwanted bowing of the product.

Because of the limitations on prior continuous processes, somemanufacturers have opted for injection or blow molding building productsone at a time. While such techniques can provide the desired detail intexture and surface finish, they are generally limited to product sizesof about 4-5 feet in length and provide product thicknesses which arepractically limited to greater than about 0.080 inches. This isgenerally because of the difficulty associated with flowing hot viscouspolymer through thin cross-sectional profiles in steel molds.Additionally, because of the known size limitations, the randomness ofindividual features on the surface of a molded product is limited. Thisresults in only a relatively small number of pattern elements, such asshingles, being molded into the relatively small surface area. Whenseveral of these products are aligned side by side on a wall or roof ofa building, for example, it is sometimes obvious to see the patternrepeated over and over again. Accordingly, there remains a need forimproved vacuum embossing techniques for use in connection with extrudedhollow thin wall profile products.

SUMMARY OF THE INVENTION

An exterior building product comprises, a polymeric unitary hollowmember having a hollow interior portion and an exterior portion, andsaid polymeric unitary hollow member being closed along all exteriorsides. According to an embodiment of the invention, the exterior sidesare unitary with the hollow member, and are either seamless or pivotalong a hinge and latch together.

A building product comprises a continuous length pattern of surfacetopography features embossed in exterior sides of a hollow member formedas a unitary extrudate. The invention further includes a process andapparatus for making the building product, wherein the exterior sidesare supported to resist collapse thereof while heat and forces areapplied during embossing, and the sides form a hollow unitary extrudatewith ribs extending between the sides. According to an embodiment of theinvention the unitary extrudate comprises a hollow extrudate wherein theinterior of the hollow extrudate is supported by mandrels afterextrusion and during embossing to resist collapse thereof. According toanother embodiment, the extrudate has unitary ribs and is folded to forma hollow configuration with the ribs interlocked. Further embodiments ofthe invention pertain to a method of making a hollow building producthaving embossed exterior surface texture elements or features formed byembossing a continuous length of a hollow unitary extrudate whilesupporting the extrudate to resist collapse thereof while heat andforces are applied during embossing.

According to another embodiment of the invention, a continuous lengthpattern of surface topography features are embossed in exterior sides ofa unitary extrudate, wherein the exterior sides having the surfacetopography features embossed therein are pivotable about a unitary hingesuch that the exterior sides close and form a hollow unitary product.Further embodiments of the invention pertain to a unitary hollow producthaving extruded unitary interior reinforcing ribs. Further embodimentsof the invention pertain to a continuous length pattern of embossedsurface texture elements embossed lengthwise in a unitary product,wherein the surface texture elements or features are irregular inrecessed depth, raised height and area pattern, to appear as randomlyshaped surface texture elements or features occurring in respectivenatural materials. Further embodiments of the invention pertain to ahollow unitary product having unitary internal reinforcing ribs andunitary exterior surface topography features formed by embossingopposite sides of the hollow unitary product. In an embodiment of thepresent invention, an exterior building material is provided whichincludes a substantially hollow, closed, thin wall profile comprising apolymeric composition, the profile including an interior-facing surfaceportion and an exterior-facing surface portion. Upon the exterior-facingsurface portion of the profile is presented a low gloss textured patterndisposed continuously along the exterior-facing surface portion. The lowgloss textured pattern has a gloss level of less than about 50 on a 60°glossmeter, and has at least one cross-machine direction texturedpattern element.

A further embodiment of the present invention provides an apparatus anda method of making an exterior building material comprising extruding afirst polymeric composition including an additive and a colorant througha die to form a polymeric profile having a substantially closed, hollowshaped form; supporting an internal surface of said hollow shaped formwith a mandrel; vacuum embossing the polymeric profile on a flexiblerotating belt to form a textured pattern, said textured pattern disposedon an exterior surface of said polymeric profile; whereby said mandrelsupports said internal surface of the hollow shaped form against acollapsing force while also assisting in providing a better vacuum seal.Following the vacuum embossing step, the embossed profile is calibrated,cooled and cut.

A further embodiment of the present invention employs a hollow extrudatesupported internally by one or more mandrels, each preferably a floatingmandrel, such as a PTFE or fluorocarbon resin coated steel mandrel or aunitary PTFE or fluorocarbon mandrel that is solid or hollow, and whichis disposed inside the extruded soft profile of the extrudate. Thepreferred floating mandrel is a rigid, low friction, internal support,which prevents the extruded shape from collapsing and prevents therubber or silicone belt from sagging and breaking its vacuum seal withits underlying perforated metal belt. The floating mandrel is preferablydisposed between the extruder and the end of the embossing step, morepreferably, from the beginning of the embossing step to about thelocation of the vacuum chamber or vacuum boxes. The vacuum boxes canthereafter assist in keeping the outer wall of the extruder profile andthe silicone belt in close proximity to the perforated metal belt byvacuum pressure.

In a further embodiment of the present invention, a continuous method ofmaking an exterior building material is provided. The method includesthe steps of extruding a first polymeric composition including adding acolorant through a die to form a polymeric sheet; vacuum embossing thepolymeric sheet on a flexible, rotating belt to form a low gloss texturepattern of about 2-20 feet in length, the textured pattern disposed onthe polymeric sheet and having a gloss level of less than about 50, andmore preferably 30 or less, on a 60° glossmeter. The textured patternincludes at least one textured element disposed in a cross-machinedirection. The process further includes forming the embossed polymericsheet into a closed, hollow shaped article; calibrating the shapedarticle; cooling the calibrated and shaped polymeric article; andcutting said cooled and calibrated shaped polymeric article.

In still a further embodiment of the present invention, an exteriorbuilding material comprising first and second substantially hollowpolymeric shell portions are joined together by a hinge and fastenedtogether by fastening means to form a substantially hollow thin wallpolymeric article. The polymeric article has a low gloss simulated woodgrain disposed on an exterior-facing surface portion thereof.

In yet another embodiment of the present invention, an extruded productcomprising an elongated member having a first side comprising a capstocklayer; and a second side comprising one or more male fastening membersdisposed along one lateral side of said second side, and one or morefemale fastening members disposed along an opposite lateral side of saidsecond side; said polymeric member being foldable along a central,longitudinal axis so as to connect corresponding ones of said male andfemale fastening members together to form a hollow, closed, thin wallbuilding material having generally a length of about 2-20 feet. Thesemale-female connections are made while the polymeric material is stillhot, so as to allow the male and female members to melt-bond together,or these connections are joined after cooling to form a mechanical jointor supporting structure.

In a further embodiment of the invention, a continuous method of makingan exterior building material is provided in which a first polymericcomposition is extruded through a die to form a polymeric profile havinga form selected from the group consisting of: shells, a substantiallyclosed, hollow shape, and a sheet. The polymeric profile is then vacuumembossed on a flexible rotating belt to form a low gloss texturedpattern of about 2-20 feet in length, the textured pattern disposed onsaid polymeric sheet having a gloss level of less than about 50 on a 60°glossmeter, and having at least one textured element disposed in across-machine direction. The embossed, polymeric profile is then formed,calibrated and cooled prior to cutting the formed, cooled and calibratedprofile.

The preferred extruded products of this invention have a hollow, thinwall having a thickness of about 0.005-0.25 inches (0.127-6.35 mm),preferably, less than about 0.100 inches, and more preferably, about0.055-0.080 inches.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate preferred embodiments of theinvention as well as other information pertinent to the disclosure inwhich:

FIG. 1 is a partial diagrammatic side plan view of a first apparatus forextruding and continuously vacuum forming a polymeric material of thisinvention;

FIG. 2 is an enlarged view of the extruded polymeric material followingthe extrusion step of the apparatus of FIG. 1;

FIG. 3 is an enlarged view of the embossed polymeric material as itexits the vacuum embosser of the apparatus of FIG. 1;

FIG. 3A is a schematic view of a seamless hollow product in the form ofa board having one or more unitary seamless interior reinforcement ribs;

FIG. 3B is a schematic view of another seamless hollow product in theform of a board having one or more unitary seamless interior reinforcingribs;

FIG. 4 is a partial diagrammatic side plan view of a second apparatusfor extruding and continuously vacuum forming the polymeric material ofthis invention;

FIG. 5 is an enlarged view of the extruded material as it exits theextruder of the apparatus of FIG. 4;

FIG. 6 is an enlarged view of the embossed polymeric material as itleaves the vacuum embosser of the apparatus of FIG. 4;

FIG. 7 is an enlarged view of the folded sheet after it exits thefolding die of the apparatus of FIG. 4;

FIG. 8 is a cross-sectional view of a semi-finished product takenthrough line 8-8 of FIG. 4;

FIG. 9 is a partial diagrammatic side plan view of a third apparatus forextruding and continuously vacuum forming the polymeric material of thisinvention;

FIG. 10 is an enlarged view of the extruded material having a high glosssurface with a grain color following the extrusion step of the apparatusof FIG. 9;

FIG. 11 is an enlarged view of the embossed material having a low gloss,textured surface and grain color following the vacuum embossing step ofthe apparatus of FIG. 9;

FIG. 11A is a schematic view of a seamless hollow product in the form ofa board having one or more unitary seamless interior reinforcement ribs;

FIG. 11B is a schematic view of a hollow product similar to that of FIG.11A and having a capstock layer.

FIG. 12 is a partial diagrammatic side plan view of a fourth apparatusfor extruding and continuously vacuum forming the polymeric material ofthis invention;

FIG. 13 is an enlarged view of the semi-finished shaped article having alow gloss, textured surface and grain decoration thereon;

FIG. 14 is a partial cross-sectional fence board of the presentinvention showing its hollow profile and alternative constructions forone or more interlocking internal strengthening ribs, and texturedsurface portions pivotally connected along a hinge, and interlockedalong a latch;

FIG. 14A is a view of a product similar to that of FIG. 14 and furtherhaving a capstock layer;

FIG. 15 is a top plan view of the extrusion, paint application, andvacuum forming chambers of a fifth preferred apparatus for vacuumforming polymeric material according to this invention;

FIG. 16 is a diagrammatic side plan view of the preferred vacuumembosser showing a loss of vacuum and product collapse; and

FIG. 17 is a diagrammatic side plan view of the vacuum embosser of FIG.16 following the introduction of a floating mandrel.

DETAILED DESCRIPTION OF THE INVENTION Introduction

The present invention is designed to make exterior building materials,such as hollow or semi-hollow (hereinafter just “hollow”) fence boards,decking, window frames, door skins and ceiling tiles or panels and somesiding and roofing products which have improved natural surfaces, suchas surfaces resembling natural wood, including texture, grain pattern,colorant pattern and low gloss. The proposed combination of extrusionprocessing with embossing, such as, by continuous vacuum embossingprocesses, is capable of enhancing product appearance by applying a lowgloss pattern of about 2-20 feet in length in any direction, including across-extrusion or cross-machine direction, to a thin wall productsurface to emulate a natural texture. Furthermore, combiningthermoplastic materials with colorants and streaker pigments, forexample, or a combination of extrusion processes with inline decoratingprocesses, such as printing, adds grain patterns as a final requisite ofa natural wood appearance. Finally, by producing building materialshaving a hollow profile, posts and rails and fence boards and deckingplanks are made from polymeric materials inexpensively, but yet havesurface texture, grain pattern and low gloss resembling natural wood.

The present invention relates to methods of producing exterior buildingmaterials having substantially hollow configurations, preferably withshaped profiles and methods of manufacturing the same. As used herein,the term “embossing” means a mechanical or chemical process that putstexture into an otherwise smooth finish. The term “gloss” is ameasurement of the reflection of light off a finished product at a givenangle of incidence and reflection. Sometimes measured using aglossmeter, it is expressed as a numerical reading. The higher the glosslevel, the shinier the surface. The term “matte” refers to low gloss oran absence of gloss. Also as used herein, the term “grain” means thedirection, size, arrangement and appearance of fibers or patterns in awood-like material, or the simulation thereof. As used herein, the terms“heat deflection temperature” is the temperature at which a polymericmaterial deflects 0.010 in. under a load of 66 or 164 psi, as defined inASTM test D 648. Also as used herein, the term “polymeric material”shall mean polymeric compositions which includes but is not limited to,compositions having, additives, such as ultra-violet light stabilizers,fillers, plasticizers, tints, and other additives, such as glass or woodfiber. The term “molded” means any number of processes, or combinationsthereof, for forming an impression in a polymeric material, includingcompression molding, transfer molding, injection molding, blow molding,autoclave molding, contact molding, pressure bag molding, vacuum bagmolding, deep draw molding, lay-up molding and spray molding, etc.

Process and Apparatus Introduction

The preferred method of this invention is best understood by referenceto the FIGS. 1-17, which will now be described. This method provides afirst apparatus 100, FIG. 1, for the continuous vacuum forming of a hotpolymeric material, including a thermoplastic or thermosettingcomposition, for example, such as polyvinyl chloride (“PVC”),polyethylene, polypropylene, polyurethane, epoxy, polyester,polycarbonate, etc., or other similar materials. The hot polymericmaterial, as shown in FIGS. 1, 4, 9 and 12, or the hot polymericmaterial shown in FIGS. 15-17 is first extruded from an extruder 20, andis then disposed upon a flexible rotating belt or vacuum embosser 30 andbetween a bottom mold belt 515 and a top mold belt 516, in FIGS. 1, 4,9, 12, 16 and 17. Each mold belt 516 and 515 of the embosser 30 issuspended, as shown in FIG. 17, between a first drive roller 520 and asecond idle roller 530 in a substantially horizontal direction. Theembosser 30 preferably contains a porous drive belt 513, 514, FIGS. 16and 17, to facilitate flexing of its rotating belt and the passing ofair or vacuum pressure. It is most preferably made from stainless steelmesh or other open forms, such as interlocking metal or polymersections, chain link, screen or hinged segments of corrosion resistantmaterial. Each of the rotating mold belts 515, 516 of the embosser 30also includes a softer, resilient mold belt 515, 516, one or bothcontaining a mold impression, such as a continuous length pattern ofsurface texture elements or features, such as, a wood grain impression,or a similar impression for producing a low gloss embossed texturedsurface, 135, 235 and 335 in FIGS. 3, 6, 11, 13, 14 and 15,respectively. The resilient mold belt 515, 516 also includes a pluralityof apertures therethrough for passing air, such as an applied vacuumpressure. Such details of vacuum embossing are further disclosed inBosler, U.S. Pat. Nos. 5,906,840; 5,314,325, 6,823,794 and 6,641,384.

The first and second rollers 520, 530 of each flexible rotating moldbelt 516 and 515 of the embosser 30 are spaced apart from one another ina generally horizontal direction such that the rotating belt 516, 515extends between them, and forms a substantially flat forming surface.The mold belt 516 and 515 is preferably made of a resilient flexiblematerial such as rubber, or rubber-like material, such as silicone orsynthetic rubber.

Each mold belt 515 and 516 and corresponding drive belt 513, 514 arefrictionally or mechanically engaged so that, by driving the drive belt513, 514 with drive axle and drive roller 520, the corresponding moldbelt 515 and 516 moves as well. The mold impression of the mold belt 516and 515 substantially retains its shape as it spins, or stretchesslightly, so there is no need for multiple sections and seams. Thecontinuous mold impression preferably is a continuous length pattern ofsurface texture elements or features on a corresponding continuous moldbelt 516 and 515. The continuous mold impression is transferred by beingimpressed by continuous vacuum embossing into the opposite sides of theproduct 60 in FIGS. 1, 3 and 3A, and the product 60′ 3B, the product 160in FIGS. 4, 6, 8 and 14, the product 160′ in FIG. 14A, the product 260in FIGS. 9, 11 and 11A, and the product 260′ in FIGS. 11B, and theproduct 360 in FIGS. 12 and 13.

In FIG. 17, vacuum boxes 508, 510 cooperate with a plurality ofapertures in the respective mold belts 516 and 515 and the open spacesin the corresponding drive belt 513, 514 to draw a vacuum against thebottom surface and the top surface, respectively, of the extruded hollowprofile 575 having the mandrel 31, or alternatively, as shown in FIGS.4, 14 and 14A to draw a vacuum against the open and foldable, extrudedprofile formed without a mandrel 31. The mold belts 515 and 516optionally includes longitudinal and lateral sections impregnated withpolymeric or resilient rubber-like material which is relativelyimpervious to air flow. Such sections are provided with a plurality ofvacuum openings, such as circles, or rectangles, etc., through which aircan pass through and be drawn by vacuum through the open weave metallicmaterial of the preferred drive belt 513, 514. Preferably the pluralityof apertures defined in the mold belt 516 and 515 are in opencommunication with respect to the vacuum sections of the drive belts513, 514. This facilitates drawing the hot extruded profile 575 of theextrudate material by vacuum against the mold impression, and by avacuum provided by the vacuum boxes 508, 510. The hot plastic, whileretaining an elevated temperature resulting from the heat of extrusionso as to remain, at least at, and preferably above its heat deflectiontemperature, is drawn onto the mold impression, and surface texture offine detail is vacuum formed by being pressed into a central region ofthe polymeric profile 575 of the material. The lateral edge portions ofthe polymeric material may or may not be impressed with vacuum formedsurface texture. A suitable support belt and vacuum manifold aredisclosed in U.S. Pat. No. 5,906,840.

The present invention further relates to creating patterns such asvariegated colors or wood grains on hollow-profile building materials,for example, decking, fencing posts, rails, boards, railing, siding andwindow framing applications, to name a few. This invention may employsprayed, painted, coated or printed capstock layers and top coat layershaving a total thickness of preferably less than 4 mils, and morepreferably 1 mil or less, which have the ability to perform well longterm, and have ample weathering performance, mildew resistance, and dirtrepellency, while simultaneously providing good adherence tothermoplastic substrates, such as those manufactured with PVC,polyethylene, polystyrene, polypropylene, either in virgin or recycledform.

With reference to the Figures, and particularly FIG. 1 thereof, there isshown a first manufacturing process line 100 for making the buildingmaterials of this invention. The manufacturing process begins as bulkresin is unloaded from railroad cars to a conveying system, into hugesilos holding up to 250,000 pounds or more of material. From these mainstorage silos, resin is conveyed to a blender, where ingredients such ascalcium carbonate, TiO₂ and other additives and micro-ingredients, areadded to create the processing compound. This precise measuring ofingredients and uniform blending under proper heating conditions can beimportant to the production of uniform, high quality building products.

After blending, the compound is conveyed to the extruder 20 where it iscarefully metered so a consistent amount of material enters the hopper10. The extrusion operation is a process in which thermoplastic resin ispushed through a heated barrel and die by one or more large, preciselytooled screws. As they turn, the screws knead and thoroughly mix thethermoplastic compound and additives such as UV stabilizers,plasticizers, blowing agents, copolymers, and/or other extrudablethermosetting resins. Both the screws and the barrel of the extruder arepreferably heated which melts the resin and makes it easier to mix andpush. The heat (300 to 400° F. for PVC), also accelerates the physicalreaction (fusion) between resin and the micro-ingredients in thecompound.

Most building products, such as siding, are extruded with twin-screwextruders. Twin-screw extrusion is preferable to single-screw extrusionbecause it heats and distributes material more evenly, resulting in aproduct with better physical properties. As the resin compound is forcedahead of the rotating screws, the very tight tolerances in the doublebarrel promote complete fusion of the ingredients. Color concentrate isadded at the extruder, which helps to produce a rich, durable, all theway through color, in each exterior building product.

Co-extrusion, is used to join two flows of molten resin compound fromtwo extruders 20 and 70 in a single die to produce an extrudate of asingle polymeric sheet comprising two layers of materials, such as asubstrate and a “capstock layer.” As used herein, the term “capstocklayer” refers to a thin protective layer added to some exterior buildingproducts to improve weatherability and color retention. The capstocklayer comprises either a single layer of polymeric material, orcomprises a multilayer having two or more polymeric layers, each ofwhich is extruded one over the other, either by coextrusion in a singleextruder, or by separate extrusion in a number of successive extruders.The one or more layers comprising the capstock layer are unfoamed andare preferably nonporous and selected to provide a visually aesthetic,finished surface and which comprise polymer compatible additivesimparting chemical and mechanical properties, for example, water andmoisture resistance, flame resistance, ultraviolet resistance, surfacetexture or finish, colorfastness, toughness, solar reflectance, wearresistance, impact resistance and stain resistance. In an embodiment ofthe invention, one or more layers of a multilayer capstock layercomprises a matrix of translucent resin or transparent polycarbonate forexample, and an alternative embodiment of an accent color streakers ofpolymeric colorant in opaque and transparent or translucent layerscomprising the capstock layer. Typically, the capstock layer materialcomprises acrylic-containing resin, such as AES, ASA, or alternatively,polyethylene or polypropylene. Capstock layer co-extrusion requires aprocessing window due to the difference in coefficient of linear thermalexpansion rates between the capstock layer and base or substrate.Missing this window often leads to unacceptable dimensional distortionor bowing of the panel, lineal, lintel or framing member, fence orboard, for example.

In FIGS. 1 and 17, as the extrudate exits the extruder 20, the polymericsheet or profile 575 is still very hot, nearly molten, and has a glossyor smooth extruded appearance 25 of its surface as shown in FIG. 2(e.g., over 50 gloss reading on a 60° glossmeter measuring reflection ata 60 degree angle). The gloss of the surface will have slightmanufacturing imperfections, such as scratches and faint lengthwisestraight lines imparted to the product by slight surface imperfectionsin the extrusion die. Such slight imperfections detract from theappearance of the surface, and leads to rejection of pieces of theproducts, which differ in gloss when compared against one another orwhich are not perfect in terms of gloss appearance. Although theextrusion process enables manufacture of straight grooves of constantwidth and depth or raised ridges of constant width and height, such doesnot duplicate the random surface features appearing on naturalmaterials, i.e. materials occurring in nature. According to anembodiment of the invention, between the extruder 20 and the calibrationdie 40 is located the mold belts 516 and 515 of the vacuum embosser 30(collectively, vacuum embossing apparatus or step). Depending on therollers or belts, fencing, and decking, products and accessories aretypically embossed in either rough cedar, wood grain or smooth orbrushed low gloss surface finishes that look like raised grain wood,rough hewn or split wood, or sanded, sealed and painted wood. Forexample, natural wood fence boards are kiln dried or air dried over timeand further are worn by the weather, all of which contribute to the woodsurface becoming a random or irregular pattern of striations of recessedsoft wood grain, and striations of harder wood grain that appear to beraised relative to the soft wood grain striations. Painted fence boardsfurther have such striations covered with fresh paint, which aresimulated by an embodiment of the invention, as described with referenceto FIGS. 3 and 3B. Hewn or split wood fence boards have further surfacetexture elements or features that are indicative of hewn or split roughwood surfaces, as described with reference to FIGS. 3, 3A, 14 and 14A.Some wood varieties, such as split cedar and Douglas fir have roughchecks in the wood surface that reappear over time, after being sandedsmooth or painted. Usually, such wood surfaces are unsanded andunpainted, since the rough surface checks reappear as defects in asanded or painted surface. For example, FIG. 3A discloses embossedsurface texture 135, which comprises embossed surface texture elementsor features, which are irregular in recessed depth, raised height andarea pattern, to appear as randomly shaped surface texture elements orfeatures occurring in respective natural materials. FIG. 3A illustratesan extruded and embossed product 60 in the absence of a capstock layerhaving an embossed surface texture 135 simulating an unpainted low glosstextured rough wood surface, produced by the embosser 30. FIG. 11Adiscloses similar surface texture 235, as well as, streaker grain color237. FIG. 3B illustrates an extruded and embossed product 60′ in theabsence of a capstock layer having an embossed surface texture 135simulating a low gloss textured wood grain pattern having raised andrecessed wood grain striations that simulate unpainted or paintedsurfaces depending upon the color, such as, wood color or paint colorthereof. Another advantage results from the embossing process toreconfigure the gloss of surface 25 and the surface defects produced bythe extrusion process by embossing the same to form a matte or low glosssurface texture 135. Further, U.S. Pat. No. 6,752,941 discloses theaddition of accent color pellets and a streaker concentrate, which isadded to the hopper 10 to produce a dispersion of accent color in anextruded product. For example, FIG. 11A discloses a product 260, in theabsence of a capstock layer and having the embossed surface texture 235and the accent color in the form of a colorant streaker pattern of graincolor 237 produced by the extruder 20. Further, for example, FIG. 14discloses a product 160, respectively, in the absence of a capstocklayer having the embossed surface texture 135 and a colorant streakerpattern of grain color 137. FIG. 14A discloses a product 160′ having acapstock layer 138 and the embossed surface texture 135 and a colorantstreaker pattern of grain color 137 in the capstock layer 138.

Some building products 60, 60′, 160, 160′, 260, 260′ and 360 are treatedwith a post-forming step or steps. Equipment, such as vacuum sizers ofthe calibration die 40 and post-formers, provide greater consistency inpost-formed thickness and profile. Post-formed locking devices insiding, for example, disclosed by U.S. Pat. Nos. 6,319,456 and6,737,008, comprise tighter tolerances and more intricate interlockingstructures, which result in higher wind load ratings. Post-formingoperations further include the calibration dies 40 including but notlimited to, pre-sizers and vacuum sizers and shaping dies (collectively,40) prior to the cooling tank 50 to create distinctive profiles and awide range of sizes for products 60, 60′, 160, 160′, 260, 260′ and 360.In a vacuum sizer as the calibration die 40, the product is given acrisp finish profile. In FIG. 3B, tongue and groove edges along oppositeside edges of a simulated board 60′ are heated at least to its heatdeflection temperature, alternatively, at least to its vicat softeningpoint temperature, sized and straightened in the calibration dies 40,for example, to obtain accurate dimensions of tongue and groove jointsections that interengage when a number of simulated boards 60′ areinstalled side by side and interlocked by tongue and groove joints, forexample, to construct a fence or a deck. Alternatively, the oppositeside edges 166, 169 of a simulated board 160 or 160′ are heated at leastto its heat deflection temperature, alternatively, at least to its vicatsoftening point temperature, sized and straightened in the calibrationdies 40, for example, to obtain accurate dimensions and to melt bond thejoint 166.

The cooling tank 50 is located after any post-forming operation. Oncethe hot sheet, including an optional, i.e. alternative embodiment of, apainted and/or printed layer over the polymeric substrate, is introducedinto the cooling tank 50, the product temperature quickly drops belowits “heat deflection temperature” and the final shape sets. Anembodiment of the invention comprises a gravure roll coater or otherform of a printer 311, FIG. 12, located between the vacuum embosser 30and the cooling tank 50. The painted and/or printed layer driesseparately from the cooling tank 50 when painted and/or printed eitherbefore or after the hot sheet is cooled in the cooling tank 50.

A coating step comprises printing by a gravure roll coater (“printroll”) comprising an exemplary embodiment of the printer 311, 312 or313, FIG. 12, which are provided and located before or after theembossing step by the vacuum embosser 30, or before or after the vacuumsizer of the calibration die 40, for example. Preferably the capstocklayer coating step occurs prior to water cooling by the cooling tank 50,so that the substrate's heat of extrusion is used to dry the capstocklayer coating. In another preferred embodiment, the coating stepcomprises printing patterns of colors by one or more computer controlledink-jet printers 311, 312 or 313, FIG. 12, that performs depositing oneor more print layers in succession, such as a 100% opaque capstock layerfollowed by depositing print layers comprising one, two or threevariegated layers that dry prior to water cooling.

After passing through the cooling tank 50, the substrate and alternativeembodiments of a painted or printed layers and/or alternativeembodiments of a capstock layer are optionally punched with openings,not shown, at precise intervals for insertion of metal supporting rods,nails or fasteners and the like. Finally, the product 60 is cut tolength at cut off, inspected and packaged.

Variegated Surfaces and Decoration

The embodiments of the invention comprise one or more spraying,painting, and/or printing steps (“coating step”) disclosed in FIG. 12,for example, which follow the extrusion step or following thealternative embodiment of a co-extrusion step to form both a capstocklayer and one or more top coat layers that provide a variegated pattern,textured and with or without a colored pattern, to the alternativebuilding material product 60, 60′, 160, 160′, 260, 260′ and 360. Thevariegated textured pattern comprises a wood grain in one or morecoating layers. The coating step includes but is not limited to, hotpainting, thermal spraying, paint spraying, fusion coating, inkjetprinting and gravure roll coating, for example. A gravure roll coater311, FIG. 12, is located between the vacuum embosser 30 and the coolingtank 50 in the preferred manufacturing schematic of FIG. 1 to performthe coating step.

The inks, pigments, coatings or paints create variegated wood grains andcolors applied by direct printing or coating, for example, is providedwithout collapsing distortion or bending of thin panels, long deckingplanks, or intricate window lineal, lintel or framing member, fences.Preferably, the total coating thickness will be less than 4 mils, andpreferably, 1 mil or less, compared to existing co-extruded ASA capstocklayers of about 4-6 mils, used in PVC siding, for example.

While various coatings are employed in connection with variegatedsurfaces of this invention, those including PVC, polyethylene,polypropylene, ASA and other acrylic-based compositions and fluorocarbonresins, such as, polytetrafluorethylene, PTFE, PFA, ETFE, ECTFE, FEP,polyvinylidene fluoride, PVDF, PPS, EFEP, TEFLON®, and otherthermoplastic or thermosetting resins, are desirable. These compositionsare applied to thermoplastic or thermosetting sheets or constructionmaterials by such techniques as thermal spraying, paint spraying, fusioncoatings, inkjet printing, and gravure roll printing, for example.

One method for making the capstock layer and the first, second, andsubsequent top coat layers of the variegated building products of thisinvention, employs a water base emulsion ink or paint containing acopolymer of PVDF and Hexa Fluoro PVDF that is polymerized in thepresence of an acrylic component. The preferred coating is sold underthe trademark Kynar® and is provided by Arkema.

The hollow building product of this invention also relates to an articlethat has a variegated effect appearance. The article comprises a mixtureof a substantially non-opaque (i.e., neither transparent nortranslucent) polymer matrix, and color particles having different meltflow properties from the polymer matrix. The initially discrete colorparticles are suspended in the non-opaque matrix, and streak out duringprocessing, acting as accent color pellets or masses. By “streak out” ismeant that the color particles extend and form variegated lines andshades of color for example the colorant streaker pattern of grain coloror grain indicia 137. The transparency or translucency of the non-opaquematrix adds a depth or dimension to the variegated appearance. Forexterior applications, at least the outermost layer, which would beexposed to the environment, is protected by appropriate antioxidants,thermal stabilizers, photostabilizers, etc.

The melt index (MI) of a polymer resin is a measurement ofprocessability under low shear rate conditions. The MI is determined byASTM D-1238 (for example, Condition E for PVC) (190° C./2.16 kg). Forinstance, the MI of the polyolefins is generally between about 0.2dg/min, and about 100 dg/min, preferably, between about 1 dg/min andabout 10 dg/min, and most preferably, between about 2 dg/min and about 8dg/min. The MI of the polymer resins are measured using ASTM D-1238.

When thermoplastic materials are heated, the thermoplastic begins tosoften, its physical properties changing in various ways. Thetemperature at which a measurable softening of the thermoplastic occurswhen heated is, preferably, measured by the “vicat” method, and isreferred to as the “vicat softening point temperature”. Analogous orrelated temperatures are measured by other methods, resulting in otherscales of temperature versus physical property, such as the heatdeflection temperature, or the melt flow index. The vicat method andscale, preferred by the present inventors, is specified by ASTM-D-1525,from which the vicat softening point temperature referenced herein wasobtained. The vicat softening point temperature indicates the softeningtemperature at which the resin begins to melt in response to increasedtemperature. The melt flow index is a measure of the viscosity of aresin when it has fully melted.

The transparent matrix material includes either a plurality of types ofcolor particles and/or accent color pellets. The variations in colorparticle type include different colors of pellets, different sizes ofpellets, different melt flow behavior of pellets, or pellets havingdifferent relative viscosities compared to the matrix polymer. Thedifferent colors will result in different sizes or shapes of streaks.The different viscosities will result in different lengths of streaks.The different kinds of pellets contribute to the complexity of thevariegation obtainable with this invention, and to the aesthetics ofsimulation of a wood grain or a mineralogical veining effect for thefinished article. Methods whereby the formation of the article areaccomplished include for example, extrusion, molding, and injectionmolding.

Furthermore, an article made by the processes of the present inventionalternatively comprises a plurality of variegation layers wherein eachof the layers includes a transparent or semi-transparent matrix, and oneor more kinds of accent color particles. The layers are formed, forexample, by extrusion of individual layers followed by lamination orbonding to construct a multilayer article. Alternatively, the variouslayers are coextruded through, for example, a plural manifold die systemto form the multilayer article in fewer steps. The articles of thepresent invention are provided with a transparent or translucentprotective overlayer or capstock layer, by means of such as lamination,coextrusion or coating applications. The coating step includes but isnot limited to, hot painting, thermal spraying, paint spraying, fusioncoating, inkjet printing and gravure roll coating, for example. Thearticle also includes a colored base layer, which color is at leastpartially visible through the non-opaque, transparent or translucent,matrix of the streaker-containing layer.

Different types of color particles include, for example, color, size andmelt rheology. Different sizes will result in different widths or shapesof color streaks. Different melt rheology or viscosity during processingwill yield different behaviors in streak flow. For example, lowerviscosity streaker particles will stretch out more on processing. Largerparticles produce wider streaks of variegation. Color particles withgreater miscibility/compatibility with the matrix polymer will producestreaks having more diffuse boundaries.

The materials of this invention comprises various transparent ortranslucent matrices which are the same or different chemical families.The layers are selected for controlling other functionality required inthe end product. The rheology of each transparent or translucent matrixare balanced for the given color particles contained therein. Each layerprovides other functionality, such as, for example, stabilization and UVprotection in the outer layers, chemical resistance, or resistance todirt pickup.

An alternative embodiment of a transparent matrix comprises atransparent colorant. This transparent colorant could be a dye or asmall particle pigment. The use of transparent color of a layercontaining a transparent colorant provides a degree of freedom inimparting a desirable depth in appearance to the article. Also, a singlecolor particle type is used in each transparent matrix, or a given layercomprises more than one kind of color particle.

The colored base or substrate layer comprises any material desired inmaking the article of the invention. For example, it comprises a filledbase polymer of less weatherable materials that are protected by theupper layers which also contribute to a desirable aesthetic. Anembodiment of the base or substrate itself comprises a plurality oflayers. In one instance, it comprises a colored surface layer adjacentto the variegation layers, with a layer containing fillers beneath. Thebase or substrate layers contribute substantially to the bulk mechanicalproperties of the article, while the variegation layers provide adesirable appearance.

Processes and Apparatus Details

In a first embodiment of the present invention, a continuous lengthhollow extrudate 60 or 60′, FIG. 3A or FIG. 3B, with a hollow, closedthin wall profile is extruded by extruder 20, shown in FIG. 1. A smooth,extruded glossy outer surface 25, FIG. 2, of this hollow, continuouscross-section piece exits the die of the extruder 20. The extrudateprofile is a hollow, closed thin wall profile in the absence of acapstock layer, which includes a thermoplastic material with additivesfor weatherability, durability, flame resistance and other desirablefeatures for an exterior product. The die of the extruder 20 is equippedwith interior pins or mandrels which are capable of forming theextrudate 60 or 60′ with hollow lengthwise sections separated bycontinuous length, unitary internal ribs 162, FIG. 3A or 3B, within thehollow thin wall extrudate 60 or 60′, the ribs 162 bridging betweenopposite interior lateral sides of the hollow thin wall extrudate 60 or60′ to support and resist collapsing forces, and to support and resistsagging from gravity before vacuum embossing. Floating mandrels 31outside of the die are connected to the pins and mandrels inside the dieby corresponding flexible, adjustable links or connections 526, FIG. 17,such as. braided steel wire, chain, cable or rope, for example, suchthat the mandrels 31 float at the ends of the links or connections 526and remain inside corresponding interior sections of the extrudate. Thecorresponding one or more low friction (e.g., cast, molded or machinedunitary PTFE or other fluropolymers or metal coated with low frictionPTFE resin or other fluoropolymers) mandrels 31, FIGS. 1, 9, 12 and 17,keep the hollow extrudate from collapsing under the applied heat andforces during vacuum embossing opposite sides of the hollow extrudate bythe top mold belt 516 and by the bottom mold belt 515. Each floatingmandrel 31 preferably extends within the vacuum embosser 30, preferablyat least up through the leading edge of the vacuum boxes 508, 510.(Alternatively, the floating mandrel 31 could be used with aconventional roll embosser.) The floating mandrels 31, FIGS. 1, 9, 12and 17, are surrounded by the interior surfaces of the respective hollowextrudate sections of the hollow extrudate 60′ while the material isconveyed between the top mold belt 516 and bottom mold belt 515 of thevacuum embosser 30. The hollow extrudate sections slide over the lowfriction mandrels 31 while being transported through the embosser 30.The smooth profile extrudate from the extruder 20 undergoes embossing inthe vacuum embosser 30, having one or more continuous rubbery mold beltscomprising the lower mold belt 515 and the upper mold belt 516 whereapplicable, embossing a continuous patterned impression of controlled,low-gloss, pattern texture 135, 235, 335 in one or more sides (oppositesides) of the extrudate 60 or 60′ having a hollow, closed thin wallprofile of continuous length, and then cut to desired lengths of about2-20 feet after emerging from a cooling tank 50. The preferred extrudedproducts of this invention have a hollow, thin wall having a thicknessof about 0.005-0.25 inches (0.127-6.35 mm), preferably, less than about0.100 inches, and more preferably, about 0.070-0.090 inches.

Thin wall hollow profiles remain hot and soft during vacuum embossing.The upper silicone belt 516 of the vacuum embosser 30 is relativelyheavy and tends to sag into the soft hollow profile, which is too thinto support the weight of the sagging silicone belt 516. This causes thetop wall of the profile to collapse. This, in turn, creates a gap “a”between the silicone belt 516 and the perforated belt 514′ releasing thevacuum. The result is poor product quality.

As shown in FIG. 16, without a mandrel to support the soft hollowextrudate, the thin wall of the profile 575, which is often less than0.010 inches in thickness, can not support the weight of the uppersilicone belt 516, and becomes vulnerable to the collapsing force of theeffect of gravity on the upper belt 516. This can be demonstrated bylooking at the internal cross-sectional dimension “c” of the profiledefined along its inner edge. As the profile 575 is extruded, it has aninternal dimension “c”. Upon entering the vacuum embosser 30, the weightof the upper mold belt 516 is exerted on the upper wall of the profile575, bending it downward to reduce the internal dimension to a smalleropening “b”, which results in an unintentional distortion of thebuilding product. Without support, the upper belt 516 tends to droop,causing a gap “a” to form between the resilient mold belt 516 and theporous drive belt 514. This gap “a” results in vacuum from the vacuumbox 510 not being maintained. The loss of vacuum causes the perforatedbelt 514 to at least partially lose frictional contact with the siliconeresilient belt 516. In addition, the weight of the resilient belt 516 isnow fully on the thin wall soft profile 575, which results in itsdistortion. The loss of vacuum pressure also prevents the outer surfaceof the thin wall soft profile 575 from being impressed into the textureof the mold or resilient belt 516, which further results in a completeor partial loss of embossing pressure, and little or no resultingpattern. It also becomes difficult for the drive belt 514 to continue tofrictionally drive the mold belt 516.

As shown in FIG. 17, floating mandrel 31 with its preferred PTFE coatingon metal or unitary member of PTFE has a flexible connection 526 to thefixed mandrel in the extrusion die, which has been shown to overcome theproblems of lost vacuum and distortion of the formed hollow profile. Byassisting in keeping the hollow profile 575 from collapsing and bymaintaining cross-sectional dimension “c” from the beginning to the endof the vacuum embossing step, the floating mandrel 31 assists inmaintaining the quality of the extruded profile 575 in both its internaldimensions and its external textural surface. The floating mandrel 31not only maintains the internal dimension of the profile 575, but alsohelps maintain the exterior wall of the profile 575 in close contactwith the resilient mold belt 516 to insure that an embossed texture ismade. Artificially supporting the interior of the extruded profile 575also helps to maintain a vacuum seal between the resilient belts 515,516 and the perforated belts 513, 514. Although the floating mandrel 31is shown extending across the length of the vacuum boxes 508, 510, itpreferably extends to at least the beginning of the vacuum boxes 508,510 or to about line “d”. This position will allow the vacuum boxes 508,510 to maintain sufficient vacuum to keep the thin wall profile 575 andthe resilient molding belt 516 in close proximity as they approach thevacuum box 510, even though a floating mandrel surface may or may not beprovided beyond the edge of the vacuum box 510.

The surface texture elements or features 135, 235, 335 are irregular inrecessed depth, raised height and area pattern having a dimension thatvaries in the cross-machine direction laterally of the continuouslength, to appear as randomly shaped surface texture elements orfeatures occurring in respective natural materials compared to a processof extrusion that is limited to producing straight length dimensions andconstant cross sectional dimensions such as a straight groove ofconstant depth or a raised straight rib of constant height. The texturedsurfaces have a gloss level of less than about 50 on a 60° glossmeter,and the texture pattern has at least one texture pattern element with adimension that varies in a cross-machine direction relative to themachine direction of the extrudate formed by extrusion. Followingembossing, the embossed sides and thin wall profile of the embossedextrudate are subject to a calibration die 40 including but not limitedto, a vacuum sizer or shaping die (collectively 40), or a combinationthereof. Following sizing or other calibration, the embossed extrudateis then cooled in a cooling tank 50, and emerges as a finished product60, 60′, 160, 160′, 260, 260′ and 360, respectively. The vacuum embosser30 provides the hollow profile with a low gloss, textured surface 135,235 and 335, respectively, which comprises a pattern of surface texturefeatures, wherein the surface texture elements or features are irregularin recessed depth, raised height and area pattern, to appear as randomlyshaped surface texture elements or features occurring in respectivenatural materials, for example, a wood grain pattern, FIGS. 3A, 3B, 11,11A and 14.

FIG. 4 discloses a second embodiment of an apparatus 200 for extrudingand vacuum embossing a low gloss surface texture 135, FIG. 6, into oneor more exterior surfaces of a hollow product 160, FIG. 14, that wouldbe susceptible to collapse or bending by the heat and forces requiredfor vacuum embossing. Thermoplastic material additives and colorants aredisposed in the hopper 10, followed by extruding through the extruder20. Following extrusion at the extruder 20, an extruded sheet extrudateis formed with a thin wall profile having a first interior major surfaceon an interior of the thin wall profile, and a second exterior majorsurface on an exterior of the thin wall profile. The extruded sheetextrudate has a unitary continuous lengthwise hinge folding 169pivotally joining a first lateral side and a second lateral side of theextruded sheet. The hinge 169 is formed preferably by extrusion in theextruder 20 or, alternatively, by embossing in the vacuum embosser 30.The extrudate comprises the hollow product 160, FIG. 14, in an open andflat configuration prior to being folded along the hinge 169 to form ahollow closed configuration. The flat configuration is supported by theupper mold belt 516 against collapse thereof while the lower belt mold515 embosses the exterior major surface of the extrudate with thepattern of embossed texture 135. A plurality of single ribs 162, FIGS.4, 5, 8, 14 and 14 a, extend continuously lengthwise and project outwardand disposed on the first lateral side formed preferably by extrusion inthe extruder 20 or alternatively formed by embossing in the top moldbelt 516 of the vacuum embosser 30 and formed unitary with the firstmajor surface, and a plurality of double ribs 164 extend continuouslylengthwise and project outward and disposed on the second lateral sideformed preferably by extrusion in the extruder 20 or by embossing in thetop mold belt 516 of the vacuum embosser 30 and formed unitary with thesame first major surface. The impression pattern in the mold belt 516 inFIG. 4 differs from the impression pattern of surface texture in themold belt 516 in FIGS. 1, 9, 12 and 17, such that the mold belt 516 inFIG. 2 is shaped to conform to the shape of the ribs 162 and 164,instead of being shaped with an embossed texture 135, 235 or 335. FIGS.14 and 14A disclose various alternative constructions of the single ribs162 and of the double ribs 164. Continuous lengthwise frictionalinterengagement 161 of an exemplary extruded or embossed, straightshaped rib 162 with and between a set of two extruded or embossedstraight shaped ribs 164 is disclosed. Continuous lengthwise latchedinterengagement 167 occurs between an exemplary rib 162 havinglengthwise unitary V-shaped latches extruded on opposite sides, andcomplementary lengthwise V-shaped latches extruded on respectiveexemplary ribs 164. Alternatively each set of the double ribs 165 ismodified by having a single rib 164 with a V-shaped latch to interengagewith the V-shaped latch of a corresponding rib 162. A continuouslengthwise adhesive bond or a melt bond interengagement 163 of anexemplary extruded or embossed shaped rib 162 with and between a set oftwo extruded or embossed straight shaped ribs 164 is disclosed. Anembodiment of an adhesive bond is formed by adding a hot melt adhesive.An embodiment of a melt bond results from heating the ribs 162 and 164at their interface by an ultrasonic welding apparatus. As long as meansfor retaining the extruded embossed profile of the sheet into a foldedclosed hollow profile product 160 once folded and joined, the exemplarysingle ribs 162 interengaging corresponding sets of two exemplary ribs164 take on any number of forms, including latched interengagement, anadhesive bond or a melt bond. Alternatively, a single rib 164 issubstituted for each set of the double ribs 64 to interengage acorresponding rib 162. The set of interengaging ribs 162 and 164 closestto the hinge 169 is the first to be interengaged and interlocked, orheated or melted and thereby interlocked, followed, in turn, by each setthat is progressively farther from the hinge 169 than a previouslyinterengaged set, while in the process of pivoting lateral sides towardeach other about the folding hinge 169 to fold the extruded embossedprofile of the sheet from an open configuration to a closedconfiguration.

In FIGS. 4 and 9 another extruder 70 of an alternative embodiment of theinvention provides by co-extrusion, a second polymer composition to forman extruded capstock layer 138 in FIGS. 14A and 238 in FIG. 11B. Acolorant, such as a streaker material is added in the hopper 10′ of theextruder 70 for adding streaks of accent grain color 137 and 237,respectively, as disclosed further by U.S. Pat. No. 6,752,941.Alternatively, the grain color 137 and 237, respectively, comprisesstreaker colorants in the extrudate formed by the extruder 20 in theabsence of a capstock layer 138 or 238, or alternatively, solely in theextrudate under the capstock layer 138 or 238, or alternatively, solelyin the capstock layer 138 or 238, or further alternatively, in both theextrudate under the capstock layer 138 or 238 and in the capstock layer138 or 238. The streaker colorants in the capstock layer 138 or 238 whenpresent comprise the entirety of the grain color 137 or 237 or,alternatively, supplement the portion of the grain color 137 or 237under the capstock layer 138 or 238 to add grain depth and color shadesto the grain color 137 or 237. Due to co-extrusion and following suchco-extrusion, the capstock layer 138 or 238 is bonded to the exteriorsecond major surface of the extrudate formed by the extruder 20 andopposite the interior first major surface comprising the single rib 162and the single or double ribs 164. The external second major surface onthe capstock layer 138 or 238, or the extruded profile in the absence ofa capstock layer, is then subject to an in-line, continuous embossingstep at vacuum embosser 30, the bottom belt 515 of which provides anembossed surface texture, preferably, on the capstock layer 138 or 238or, alternatively on the second major surface of the extruded profile ofthe sheet, as disclosed by FIGS. 3A, 11A and 14 in the absence of acapstock layer 138 or 238.

The capstock 138 or 238 provides a weather durable layer covering andprotecting the core or base material of the vacuum molded product. Anadvantage results from vacuum molding the surface topography recesses135 in the weather durable capstock 138 or 238 compared to etching,stamping or abrading to remove capstock material. The vacuum moldedcapstock 138 or 238 retains its desired thickness under each surfacetopography recess 135 formed by vacuum molding to maximize the thicknessof the weather durable protection. The less viscous core or basematerial flows to become thinner. Thereby, the vacuum formed capstock138 or 238 has a maximized thickness of weather durable protection,compared to etching, stamping or abrading to remove capstock material,which reduces the thickness and the useful life of the weather durableprotection.

The extruded embossed profile of the folded sheet, FIGS. 14 and 14A, isconveyed through a set of folding dies 175, or similar equipment, whichfolds the extruded embossed profile of the sheet along the hinge 169into a folded sheet 180, FIGS. 8, 14 and 14A, of a closed hollow product160, 160′ having a hollow profile and with the embossed second majorsurface on the extrudate or on the alternative embossed capstock layer138 or 238 on the extrudate facing outward and comprising multipleexterior embossed sides of the closed hollow product 160, 160′. In FIG.4, the folding dies 175, or joining device 177, or both, are used tojoin the single rib 162 with the single or double ribs 164 and form acontinuous lengthwise joint 166, for example, a continuous tongue andgroove joint 166, with the continuous tongue formed on one lengthwiseedge of the extruded embossed profile of the sheet and the continuousgroove formed on an opposite lengthwise edge of the extruded embossedprofile of the sheet. The folding dies 175 fold the extruded embossedprofile of the sheet along the hinge 169, while the joining device 177applies hot melt adhesive, or heat to melt the lengthwise continuoussurfaces of the ribs 162 and 164 such that when the hollow profile iscompletely closed an adhesive bond or melt bond is formed therebetween,followed by complete folding and closing of the hollow profile causingthe tongue and groove of the interlocking joint 166 to interengage andlatch the hollow profile in a closed configuration. The joining device177 further applies hot melt adhesive or melts the tongue and groovejoint 166 to form and adhesive bond or melt bond. Alternatively, thefrictional interengagement or latched interengagement and retention ofthe ribs 162 and 164 occur while the hollow profile is folded andclosed. This is followed by calibration, sizing, or shaping by operationof calibration dies 40, and finally, a cooling tank 50.

The finished product 160, 160′ has a closed hollow profile, shown inFIGS. 8, 14 and 14A, in which the single rib 162, alternatively thesingle rib 162 joined to respective double ribs 164 by beingmechanically joined or melt bonded, for example, to the double ribs 164,to form preferred reinforcing supporting rib structures bridging acrossthe hollow interior from one lateral side of the interior surface to theother lateral side of the interior surface. The product 160, 160′preferably includes a tongue and groove, glued, mechanical or melt bondjoint 166 used to clasp or retain the hollow profile into a closedstructure, as well as a preferred hinge element 169 which allows thefirst and second shell portions or lateral sides of the structure to bepivoted or rotated about the hinge 169 and interengage or clasped toform the joint 166.

The preferred capstock layer, 138 or 238 or, alternatively, the exteriorsecond major surface of the product 60, 160 or 260 in the absence of thecapstock layer 138 or 238, includes streaks of a grain color 137 or 237and embossed texture 135 or 235, as substantially shown in FIGS. 3A, 8,11, 11A, 11B, 14 and 14A. Depending on the temperature of the polymericmaterial at the folding die 175 and joining device 177, the joint 166comprises a mechanical connection or melt bond connection, and theconnection between the single ribs 162 and double ribs 164 comprises amechanical or melt bond, or some combination thereof. Similarly, thehinge 169 comprises, for example, a softened portion of the sheet, dueto its elevated temperature at this stage of the process.

With reference to FIG. 9, there is shown a third apparatus 300 forextruding and vacuum forming polymeric material pursuant to thisinvention. This process employs an extruder 20 as in FIG. 1, and analternative process comprises an extruder 70 which forms a coextrudedcapstock layer 238 in FIG. 11B in which the capstock layer 238 comprisesthe surface topography recesses 235 and the color enhancing wood grainsuch as the pattern of grain color 237. Following the co-extrusionoperation, the extrudate has a high gloss surface 238 and the graincolor 237 in FIG. 10. In this embodiment, the extrudate has a closedthin wall profile 260 in FIG. 11A without a capstock layer, or profile260′ with the capstock layer 238, FIG. 11B, and colorant enhancing woodgrain 237 for providing the final effect of a wood appearance, includinggrain color 237 and low gloss texture 235. The grain color 237 comprisesstreaker colorants in the extrudate, FIG. 11A, in the absence of acapstock layer or alternatively in either the extrudate under thecapstock layer 238 or the capstock layer 238, or further alternatively,in both the extrudate under the capstock layer and the capstock layer238 to provide differences in grain color and differences in depth ofgrain color beneath the capstock layer 238.

The die of the extruder 20 is capable of converging the basethermoplastic for the substrate with a second thermoplastic materialfrom the extruder 70 creating an outer layer or capstock layer 238 onthe top of the first plastic material. This die of the extruder 20 has alow friction, floating mandrel or mandrels 31 so as to maintain a thinwall “hollow” product 260 or 260′ with unitary internal ribs 162 similarto that of the product 60, FIG. 3A, produced by the process of FIG. 1.The floating mandrel or mandrels 31 are used to support the profileinterior to resist collapse thereof during the vacuum embossing step.Second, third or more thermoplastic materials in the extrudatepreferably have colorants, such as dyes, pigments and inks, etc., whichcreate a wood grain color 237 appearance for example. The hollow profileis then subject to a vacuum embosser 30 with one or more rubbery beltsto create an embossed surface texture 237, such as a wood texture, onone or more sides of the final product 260 or 260′, followed by theapplication of vacuum sizing, calibrating or shaping steps bycalibration die 40 and a cooling tank 50 to produce a final product 260or 260′.

As shown in FIG. 12, a fourth apparatus 400 for extruding andcontinuously vacuum forming a polymeric material is provided. In thisapparatus 400, alternative “decorating” step(s), such as printing, toenhance wood-like appearances, create a wood grain on thin wall profilesby operation of printing techniques, preferably, gravure printing, rollprinting, jet printing, water transfer printing, or hot foil transferprinting. As in the earlier apparatus, thermoplastic material, additivesand colorants are disposed in pellet form into the hopper 10. The hopper10 and extruder 20 is provided. An alternative embodiment comprises theextruder 70 and hopper 10′ for a capstock layer 238. When a hollowprofile is desired, low friction, floating mandrels 31 are used as inearlier embodiments. In an alternative embodiment a hot paintapplicator, sprayer or printer 310 or 410, FIG. 15 or 12, performsin-line decorating by applying a painted wood grain to supplement orincrease the wood grain of the streaker grain color of the colorants inthe extrudate without a capstock layer and/or in an alternativeembodiment of a capstock layer as well as the earlier stated printingtechniques. As shown in FIG. 13, the decorating step combined with theembosser 30 provide supplemented grain color 337 along with low glosstexture 335 on the product 360. A printer 312 performs the decoratingstep wherein supplemented wood grain is applied during vacuum embossing,or after vacuum embossing by printer 311, or after the cooling tank 50,by printer 313. The paint or inks from one or more paint applicators310, 410 or printers, alternatively 310, or 410, 311, 312 and/or 313 areapplied after each previously applied ink layer cools to solidification,so that they provide overlapping and contrasting color, or are appliedprior to cooling and solidification of one or more previously appliedinks, so that the inks or colorants blend. Alternatively, the extrudedembossed product comprises a random or irregular pattern of striationsof recessed soft wood grain, and striations of harder wood grain thatappear to be raised relative to the soft wood grain striations, as inFIG. 3B. Painted fence boards are simulated further by having suchstriations that appear with a coating of fresh paint applied by thepainter 310, 410, as described with reference to FIGS. 12 and 17.Accordingly, the extruded embossed product of FIG. 3B comprises apainted board having a random or irregular pattern of striations ofrecessed soft wood grain, and striations of harder wood grain thatappear to be raised relative to the soft wood grain striations, whenpainted by the painter 310, 410. Further, the painting operation coverssurface defects, for example, surface color defects and surfaceabrasions.

As shown in FIG. 14, a fence board product 160 is provided having asubstantially hollow profile, with a hinge 169, one or more sets ofcontinuous lengthwise double ribs 164 combined with correspondingcontinuous lengthwise single ribs 162. The fence board product 160,alternatively comprises a single rib 162 with a frictionalinterengagement and retention 161 with a set of two ribs 164, or furtheralternatively, a set of two ribs 164 having complementary hook shapedlatching surfaces 167, 168 interengaged and latched to complementarylatching surfaces on opposite sides of a corresponding rib 162therebetween. Alternatively, a series of full length double ribs 164 andsingle ribs 162 are provided for structural support through the hollowthickness of the fence board 160. A tongue and groove joint 166 isprovided by extrusion at the respective edges of the extrudate, which,preferably, includes a mechanical locking or clasping arrangement,although this could easily be a melt-bond if the temperature of theprofile is high enough upon joining, or heat is applied to the joint 166during the joining step of the joining device 177, such as by a heatedsizer of the calibration dies 40. As shown by the fence board product160, a texture 135 and streaks of a grain color 137 are provided. Thestreaks of a grain color 137 represent a different color, contrastcolor, in the surface of the fence board product 160, while the texture135 represents low gloss peaks and valleys of surface texture, a directresult of the vacuum embosser 30.

In FIG. 15, an extrusion, paint application and vacuum forming chamberis provided in a fifth apparatus 500 for vacuum forming polymericmaterial according to this invention. A thermoplastic material withadditives and colorants is extruded from extruder 20 without a capstocklayer, or alternatively with a capstock layer 138 in FIG. 14A formed byextrusion of second thermoplastic materials with colorants and additivesin the extruder 70 as an alternative embodiment of the invention. Theextruder 70 forms the capstock layer 138 on one major surface on oneside (capstock layer) on the extruded strip (substrate) extrudate formedby the extruder 20 and the capstock extruder 70. The extrudate is about2-20 feet in continuous length. An alternative embodiment of a decoratoror paint applicator or printer 410 is provided to increase or supplementthe appearance of wood grain color 137 by the application of additionalcolorants, such as by the printer 410. The extrudate with its printedstreaks of a grain color or grain indicia 137 passes on to an embosser425 in which vacuum or pressure forming equipment with one or moreforming chambers (two illustrated) with mold impression(s) of a lowgloss, wood-like texture 135 being impressed into the extrudate on theexterior major surface of the product 160 in FIG. 14 or the product 160′in FIG. 14A. The extrudate comprises the hollow product 160, FIG. 14 orthe product 160′ in FIG. 14A, in an open and flat configuration prior tobeing folded along the hinge 169 to form a hollow configuration. Theflat configuration is supported against collapse thereof while theembosser 425 embosses the exterior major surface of the extrudate withthe pattern of embossed texture 135. The semi-finished component, about2-20 feet in continuous length, comprising the extrudate with thetexture 137, is then passed on or conveyed on rails 414 and 416 on to aforming station 420 having, for example, the folding die 175 in FIG. 4and the joining device 177 in FIG. 4, in which an embodiment of theembossed extrudate product is further formed and joined by gluing, meltbonding, welding, or via mechanical means, to form a low gloss, texturedand hollow thin wall product 160 in FIG. 14 or, alternatively 160′ inFIG. 14A. Ideally, both lateral sides of the embossed extrudate areunitary with each other along the hinge 169 and are folded and closed byjoint 166, for example, such that the texture 135 and streaks of a graincolor or grain indicia 137 are impressed into the product, e.g., foursides, for example.

EXAMPLE A

A fence board trial was conducted using new embossing belts on a vacuumforming machine with belt cooling fans. The following compositions wereemployed:

substrate: PVC with additives such as stabilizers, lubricants, impactmodifiers, calcium carbonate and titanium dioxide for UV protection.

capstock layer: ASA with additives such as stabilizers, lubricants,impact modifiers, calcium carbonate and up to 10 parts of titaniumdioxide for UV protection.

This product was made in a co-extrusion process in which substratematerial PVC was extruded through a die by a first extruder, andcapstock layer ASA material was extruded into the same die from anotherdirection by a second extruder using the following settings:

Extruder Conditions For Example A Extruder Barrel Main-Extrusion Core orCo-extrusion (ASA) Zones (BZ1-BZ4) Base Material Temperature TemperatureBZ1 (Throat) 370 330° F. BZ2 360 330° F. BZ3 320 340° F. BZ4 310 340° F.Screw Oil Heater 310 290° F. Temperature Die Temps 350 350° F. ScrewMotor RPM 700 800 Hopper Feed Motor 150 80 RPM Belt Vacuum Inches −14″Hg Dry Sizer (D.S.) −5″ Vacuum Ballast Tank −5″ Vacuum

Both the substrate and capstock layer materials merged in the extrusiondie and exited the die orifice (exit) as a single hollow shape thin wallproduct made of two materials with each of them having differentcompositions.

The following color settings, sequences and measurements were made:

Color Settings For Example A White Base Feed Pounds/Hour 85 (lb/hr)Color Feed (lb/hr) n/a Brown Streaker Base Feed (lb/hr) 85 Color Feed(lb/hr) 650 Clay Base Feed (lb/hr) 85 Color Feed (lb/hr) 400 TimberStreaker Base Feed (lb/hr) 85 Color Feed (lb/hr) 650

The trial sequence was:

a. started with white pellets;

b. added Brown Streaker pellets 54120-A4 from Americhem (still using PVCbase);

c. changed to ASA/Clay pellets; and

d. added Timber Streaker pellets 9062-A3 from Americhem (Centrex basedcolor concentrate).

The melt temperature for PVC was 390° F.; for ASA it was 405° F. Theprofile strung up very easily once again with little or no difficultyattaining vacuum.

Auxiliary fans were used on both top and bottom belts for cooling. Thebelt temperature was approximately 205-210° F. A belt temperature below200° F. will dramatically prolong the belt life. All dimensions wereachieved with puller and belt speed adjustments. Currently, there isonly one color feeder per extruder. Streaked color will typicallyrequire two feeders.

The hollow shape thin wall profile exited the die in a soft state with ahigh temperature and low rigidity. It then entered a system made of one,two, or more flexible rotating belts being strategically placed on theside(s) of the product where surface texture is required. In order forthe texture transfer process to take place, the product had to be in asoft state. Vacuum was employed to draw the product toward the texturedsurface of the belt. For the vacuum force to take action, the vacuumchamber must be sealed. Due to its soft state, the extruded profile byitself can not support its own weight and the weight of sagging flexiblebelt. As such, the vacuum chamber is not sealed and texture transferdoes not take place.

A floating mandrel(s) made of PTFE (or any other rigid material with alow friction surface) was employed to increase the rigidity of thesystem and close the seals between vacuum chamber, rotating flexiblebelts, and constantly moving forward soft extruded product, Thisfloating mandrel(s) was attached by flexible means to the stationarymetal mandrel(s) of the extrusion die. During the extrusion process, thefloating mandrel located itself in such a position in respect to thevacuum chamber, that it sealed the extruded hollow shape thin wallproduct floating over the mandrel(s), which helped to seal in the entirebelt system. This enabled the applied vacuum to pull the extrudedproduct against the textured belt surface so that texture transfer tookplace.

After exiting the rotating flexible belts, the extruded product with adesired texture entered a vacuum calibration die with a cooling tankfollowing the calibration process. In the final step of this process,the extruded product was cut to a desired length.

The final product had improved texture, definition and lower uniformgloss, when compared to a fence board of the same composition, butwithout texture.

These were deemed to be very positive results. All of the colors andmaterial combinations produced very good looking samples. The BrownStreaker was not used in conjunction with any base colors, so it wasjust streaks on a light background color. Timber Streaker didn't providemuch of a streaking effect because it melted so quickly in the ASA.Mandrels are attached to the die by wire and stainless steel fasteners,such as, eyebolt, 304 SS, 3/16″-24, 2″ shank, 1″ thread. McMaster Carrp/n 9489T81.

The resulting board had a textured pattern with a gloss reading of 27 ona 60° glossmeter, whereas a smooth PVC board made of the same materialshad a gloss reading of 33 on a 60° glossmeter. The gloss was measuredwith Glossmeter Model 500-60°, manufactured by Erichsen TestingEquipment.

EXAMPLE B

A white fence board was produced by co-extrusion using a parallel screwextruder 125 mm. screw diameter to extrude PVC substrate, and a conicaltwin screw extruder 62 mm. screw diameter to extrude PVC capstock.

substrate: PVC pellets with additives such as stabilizers, lubricants,impact modifiers, calcium carbonate and titanium dioxide for UVprotection

capstock layer: PVC pellets with additives such as stabilizers,lubricants, impact modifiers, calcium carbonate and up to 10 parts oftitanium dioxide for UV protection. PVC capstock is used for light colorproducts. (In our situation, PVC capstock is used to produce whiteboards or light color boards).

The melted PVC substrate and melted PVC capstock merged in the extrusiondie and exited the die orifice (exit) as a single hollow shape thin wallproduct made of two PVC based materials with each of them havingdifferent compositions. The melt temperature for PVC was 390 deg F. Thehollow shape thin wall product after exiting the die has smooth (flat)external surface.

The product was made with extruders settings as in the below table:

Main-Extrusion Core or Extruder Barrel Base Material TemperatureCo-extrusion (PVC) Zones (BZ1-BZ4) (° F.) Temperature (° F.) BZ1(Throat) 370 350 BZ2 360 340 BZ3 320 320 BZ4 310 310 Screw Oil Heater310 300 Temperature (° F.) Die Temps (° F.) 350 350 Screw Motor RPM 700800 Hopper Feed Motor 150 80 RPM

After exiting die the hot and flexible hollow shape thin wall productwith smooth (flat) outside surface was pulled over floating low frictionrigid mandrels attached by flexible means to pins in the die andsuspended between silicone belts of the equipment having a texturedsurface.

The settings of the vacuum belt velocity were set to equal the exitingextrusion velocity of the thin wall hollow shaped product of 12 feet perminute, as in the below table:

Belt Speed 34.0 Hz rheostat setting Belt Vacuum −14 inches Hg

After exiting the rotating flexible belts, the extruded product with adesired texture entered a vacuum calibration die with a cooling tankfollowing the calibration process. The set up of the calibration die andballast vacuum tank was as in the below table:

Dry Sizer Vacuum −5 inches Hg. Ballast Tank −5 inches Hg. Vacuum

In the final step of this process, the extruded product was cut to adesired length.

EXAMPLE C

A fence board was produced by co-extrusion similarly as in Example B,except for Example C comprising ASA capstock material substituted forthe PVC capstock material of Example B.

capstock layer: ASA pellets (with additives such as stabilizers,lubricants, impact modifiers and titanium dioxide for UV protection. ASAcapstock is used for dark color products, for example, dark brown andclay color boards.

Color concentrate pellets were added to both materials at the same pointas the material using separate single-screw color feeders with settingsas in the below table:

Clay Base Feed PVC (substrate) - 400 lb/hr. Color concentrate - 1 lb/hr.Capstock ASA feed - 100 lb/hr. Color concentrate - 4 lb/hr. Brown BaseFeed (substrate) - 400 lb/hr. Color concentrate - 1 lb/hr. Capstoek ASAfeed - 100 lb/hr. Color concentrate - 4 lb/hr.Capstock extrusion rate is 100 lb/h. Color concentrate was fed to thecapstock material at a rate of 4 lb/hr. Substrate extrusion rate was 400lb/hr. with the color concentrate added.

PVC substrate with colorant and ASA capstock with colorant merged in theextrusion die and exited the die orifice (exit) as a single hollow shapethin wall product made of two materials: PVC substrate and ASA capstock.The melt temperature for PVC was 390 deg F. and for the ASA capstock was405 deg F. The hollow shape thin wall product after exiting the die hassmooth (flat) outside surface. The product was produced with extruderssettings as in the below table:

Main-Extrusion Core or Base Material Temperature Co-extrusion (ASA)Barrel Zones (B1-B4) (° F.) Temperature (° F.) BZ1 (Throat) 370 330 BZ2360 330 BZ3 320 340 BZ4 310 340 Screw Oil Heater 310 290 Die Temps 350350 Motor RPM 700 800 Feed 150 80

After exiting die the hot and flexible hollow shape thin wall productwith smooth (flat) outside surface was pulled over floating low frictionmandrels attached by flexible means to pins in the die and suspendedbetween silicone belts of the equipment changed from flat (smooth)external surface for impression in the product to a textured surface.

EXAMPLE D

According to Example D, a fence board was produced similarly as ExampleC and with streaker pellets added to the capstock layer of Example D.

substrate: PVC with additives such as stabilizers, lubricants, impactmodifiers, calcium carbonate and titanium dioxide for UV protectioncapstock layer: ASA pellets (with additives such as stabilizers,lubricants, impact modifiers and titanium dioxide for UV protection. ASAcapstock is used for dark color products, for example, dark brown andclay color boards. Streaker pellets #58437-87 from Americhem Inc.,Cuyahoga Falls, Ohio 44221, added at a rate of 2 lb/hr (corresponding toa feeder setting at 200).

Color concentrate pellets were added to both materials at the same pointas the material using separate single-screw color feeders with settingsas in the below table:

Clay Base Feed PVC (substrate) - 400 lb/hr. Color concentrate - 1 lb/hr.Capstock ASA feed - 100 lb/hr. Color concentrate - 4 lb/hr. Streaker - 2lb/hr. Brown Base Feed (substrate) - 400 lb/hr. Color concentrate - 1lb/hr. Capstock ASA feed - 100 lb/hr. Color concentrate - 4 lb/hr.Streaker - 2 lb/hr.

From PVC substrate with colorant and ASA capstock with colorant andstreaker merged in the extrusion die and exited the die orifice (exit)as a single hollow shape of thin walls made of two materials: PVCsubstrate with colorant, and ASA capstock with colorant and streaker.The melt temperature for PVC was 390 deg F. and for the ASA capstock was405 deg F. The hollow shape thin wall product after exiting the die hassmooth (flat) outside surface.

The product was produced with the same, extruder(s) settings, beltsettings and vacuum calibration die settings as for Example C.

The patents and applications referred to are hereby incorporated byreference herein.

From the foregoing description, an invention provides exterior buildingmaterials that include hollow, closed, thin wall profiles comprising apolymeric composition including additives and colorants. The exteriorfacing surface of the profile includes a low gloss, textured patterndisposed continuously along the exterior facing surface portion forabout 2-20 feet. The present invention provides texture, pattern and lowgloss similar to real wood products. The combination of extrusionprocessing with continuous vacuum embossing processes is capable ofenhancing product appearance by applying a low gloss pattern in anydirection, including the cross-extrusion direction, to thin wall productsurfaces so as to emulate wood texture. In particular, hollow profileextrusion in combination with continuous vacuum embossing processes canbe used to produce useful building materials emulating a naturaltexture. Furthermore, the combination of thermoplastic materials withcolorants and/or a combination of extrusion processes with in-linedecorating processes will add grain as a final parameter of natural woodfence boards, decking and other exterior building products.

1. A building product comprising: a unitary extrudate having unitaryreinforcing ribs; a continuous length pattern of surface topographyfeatures embossed in exterior sides of the unitary extrudate, whereinthe sides are supported to resist collapse thereof while heat and forcesare applied to the sides during embossing; and the sides form a hollowunitary extrudate with the ribs extending between the sides.
 2. Thebuilding product of claim 1, wherein the unitary extrudate comprises ahollow extrudate supported by mandrels inside the hollow extrudateduring embossing to resist collapse thereof.
 3. The building product ofclaim 1, wherein the unitary ribs divide the extrudate into lengthwiseinterior sections, wherein the sections surround respective mandrelsinside the hollow extrudate during embossing to resist collapse thereof.4. The building product of claim 1, wherein the sides of the unitaryextrudate are joined by a unitary hinge, and the sides being pivoted andclosed together to form a hollow unitary extrudate.
 5. The buildingproduct of claim 1, further comprising: the unitary ribs comprisingfirst ribs on a first side of the extrudate and second ribs on a secondside of the extrudate; the sides being joined by a unitary hinge,wherein the sides are pivoted and closed together to form the hollowunitary extrudate; and the first ribs interlock with the second ribs. 6.The building product of claim 1 wherein exterior surface portions of thepolymeric unitary hollow member comprise a low gloss textured patternhaving a gloss level of less than about 50 on a 60° glossmeter.
 7. Thebuilding product of claim 1, comprising: the unitary extrudatecomprising a polymeric unitary hollow member either with a capstocklayer or without a capstock layer, and with or without streaker materialin the unitary extrudate.
 8. The building product of claim 1 wherein thepolymeric unitary hollow member is seamless along said all exteriorsides.
 9. The building product of claim 1, comprising: one or moreunitary ribs in the hollow interior portion.
 10. The building product ofclaim 9 wherein each rib divides the hollow interior portion intocavities, wherein each rib is seamless within the hollow interiorportion.
 11. The building product of claim 9 wherein the ribs latch toone another.
 12. The building product of claim 1 wherein the polymericunitary hollow member comprises a coextruded substrate and a weatherresistant capstock layer, wherein the capstock layer retains itsthickness beneath the low gloss textured pattern to maximize a weatherresistant thickness of the capstock layer.
 13. The building product ofclaim 1 wherein the polymeric unitary hollow member comprises anextrudate without a capstock layer.
 14. A method of making a buildingproduct, comprising: extruding a unitary extrudate; forming unitaryreinforcing ribs on the unitary extrudate; embossing a continuous lengthpattern of surface topography features in exterior sides of the unitaryextrudate; and supporting the sides to resist collapse thereof whileheat and forces are applied during embossing.
 15. The method of claim 14further comprising: supporting the interior of the extrudate by mandrelsduring embossing to resist collapse thereof.
 16. The method of claim 14,comprising: extruding the unitary extrudate as a polymeric thin wallmember with or without a unitary capstock layer and with or withoutstreaker material in the unitary extrudate.
 17. The method of claim 16,comprising: vacuum embossing an exterior of the thin wall member to forma low gloss textured pattern having a gloss level of less than about 50on a 60° glossmeter; calibrating a profile of the thin wall member;cooling said profile after calibrating the profile; and cutting saidthin wall member to a length of about 2 feet to about 20 feet.
 18. Themethod of claim 14, comprising: extruding the unitary extrudate as acoextruded substrate and a weather resistant capstock layer, wherein thecapstock layer retains its thickness beneath the low gloss texturedpattern to maximize a weather resistant thickness of the capstock layer.19. Apparatus for making a hollow polymeric building product,comprising: extruder means for extruding a unitary polymeric extrudatewith or without a capstock layer; a vacuum embosser for embossingsurface texture in exterior surfaces of the extrudate while supportinginterior surfaces of the extrudate; and a forming die for forming theextrudate into the polymeric building product.
 20. The apparatus ofclaim 19, comprising: mandrels supporting the interior surfaces of theextrudate while embossing the surface texture, or a mold belt supportingthe interior surfaces of the extrudate while embossing the surfacetexture, or a mold chamber supporting the interior surfaces of theextrudate while embossing the surface texture.